The mutualistic symbiotic system formed by clumping arbuscular mycorrhizal fungi (AMF) and plants can remediate heavy metal -contaminated soils. However, the specific mechanisms underlying the interaction between AMF and inter -root microbial communities, particularly their impact on organic phosphorus (P) cycling, remain unclear. This study investigated the gene regulation processes involved in inter -root soil phosphorus cycling in wetland plants, specifically Iris tectorum , following inoculation with AMF under varying concentrations of chromium (Cr) stress. Through macro-genome sequencing, we analyzed the composition and structure of the inter -root soil microbial community associated with Iris tectorum under greenhouse pot conditions. The results demonstrated significant changes in the diversity and composition of the inter -root soil microbial community following AMF inoculation, with Proteobacteria, Actinobacteria, Chloroflexi, Acidobacteria, and Bacteroidetes being the dominant taxa. Under Cr stress, species and gene co -occurrence network analysis revealed that AMF promoted the transformation process of organic phosphorus mineralization and facilitated inorganic phosphorus uptake. Additionally, network analysis of functional genes indicated strong aggregation of ( pstS, pstA, pstC, TC.PIT, phoR, pp-gppA ) genes, which collectively enhanced phosphorus uptake by plants. These findings shed light on the inter -root soil phosphorus cycling process during the co-remediation of Cr -contaminated soil by AMF- Iris tectorum symbiosis, providing valuable theoretical support for the application of AMF-wetland plant symbiosis systems to remediate heavy metal -contaminated soil. (c) 2024 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.
